The present invention relates to measuring human/mechanism interfaces, and more particularly to such measurement systems that relate to the measurement of relatively small one degree of freedom mechanisms, such as switches.
As the market for sales of products becomes more competitive, a manufacturer must distinguish its products from the competition. Thus, a product design may require more than providing the proper function—it may also require providing a certain feel or image for the product. For example, a small mechanism, such as a switch, may need to not only perform its function of adjusting the operation of a product, but also provide a certain feel to the switch operator while being actuated. Such a switch feel may give an impression of quality or distinctiveness to the product, and one may wish to have this particular feel for all of the switches on a given product—that is, a switch feel harmony. Thus, the feel of a switch may be almost as important as the function the switch performs. In order to define and achieve this feel, the human/machine interface for that particular switch must be defined.
In addition, for many manufacturers, the switches are fabricated by multiple suppliers. In order to maintain switch feel harmony, then, one must be able to not only define the switch feel characteristics in a quantitative and objective manner, but also possess an ability to measure the switches produced by the suppliers, in an accurate and reliable way, in order to verify that the switches meet the criteria. Consequently, an accurate and repeatable way to define and measure switches is needed.
Conventionally, measurements for determining characteristics of switches were accomplished by mounting the switches in laboratory type fixtures and connecting them to a switch measurement device. Typically, these measurement devices measured the peak force or torque that was applied during switch actuation and possibly also the range of motion. Mostly, though, the feel of such switches was determined by consensus in panel studies. This conventional approach, however, does not produce a quantitative, objective, verifiable, and repeatable means for completely measuring the feel of a switch.
As a result, some of the more advanced systems employ a laboratory type fixture with a more advanced measurement device that can measure the force applied to the switch as the switch moves through its range of motion. This force/displacement profile (or torque/angular displacement for a rotary switch), then, provides a more complete definition of the switch properties. And, since each fixture is tailored to the particular switch being measured, the accuracy and repeatability can be high. However, having a separate fixture for each particular switch being tested is an expensive and time consuming way to measure switch characteristics. This is particularly true for products such as automotive vehicles, which have many switches of varying types and sizes.
For switches that rotate or pivot in particular, the switch measurement system must be able to properly grip and/or contact the switch while manipulating the switch about its pivot axis. Preferably, this is accomplished for multiple types of rotating and pivoting switches, all while minimizing the time and effort needed to change from measuring one type of rotating or pivoting switch to another. Of course, in providing the flexibility to switch between measurements of different types of switches, the need to maintain the accuracy for all types being measured is desired.